Article

Tetradactyl Footprints of an Unknown Affinity Theropod Dinosaur from the Upper Jurassic of Morocco

Institut de Biologia Evolutiva - Universitat Pompeu Fabra, Spain
PLoS ONE (Impact Factor: 3.23). 12/2011; 6(12):e26882. DOI: 10.1371/journal.pone.0026882
Source: PubMed

ABSTRACT

New tetradactyl theropod footprints from Upper Jurassic (Oxfordian-Kimmeridgian) have been found in the Iouaridène syncline (Morocco). The tracksites are at several layers in the intermediate lacustrine unit of Iouaridène Formation. The footprints were named informally in previous works "Eutynichnium atlasipodus". We consider as nomen nudum.
Boutakioutichnium atlasicus ichnogen. et ichnosp. nov. is mainly characterized by the hallux impression. It is long, strong, directed medially or forward, with two digital pads and with the proximal part of the first pad in lateral position. More than 100 footprints in 15 trackways have been studied with these features. The footprints are large, 38-48 cm in length, and 26-31 cm in width.
Boutakioutichnium mainly differs from other ichnotaxa with hallux impression in lacking metatarsal marks and in not being a very deep footprint. The distinct morphology of the hallux of the Boutakioutichnium trackmaker -i.e. size and hallux position- are unique in the dinosaur autopodial record to date.

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    • "17–19). Theropod hallux impressions are not common, but they do occur and have been reported in the literature (Lockley and Hunt, 1994; Harris et al., 1996; Harris; 1997; McCrea, 2000; Lockley et al., 2004; Nouri et al., 2011; Xing et al., 2013c; McCrea et al., 2014a, b; Xing et al., 2014). The recognition of a small digit trace medial to the weight-bearing digits is sufficient to identify the impression as the hallux, a normal occurrence and not an example of polydactyly. "
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    ABSTRACT: Literature concerning dinosaur footprints or trackways exhibiting abnormal gait or morphology reflecting pathology (ichnopathology) is rare. We report on a number of Jurassic and Cretaceous occurrences of theropod footprints from western North America with unusual morphologies interpreted herein as examples of inferred pathologies, or ichnopathologies. The majority of ichnopathologies are primarily manifested in the digit impressions and include examples of swelling, extreme curvature, dislocation or fracture, and amputation. A number of occurrences are single tracks on ex situ blocks with substantial deformation (inferred dislocation or fracture), or absence of a single digit impression. Two occurrences are from in situ natural mould trackways, one of which is a lengthy trackway of a presumed allosauroid with no noticeable deformation of the digits or feet but with strong inward rotation of the left footprint toward the midline and a pronounced, waddling limp. The other is a tyrannosaurid trackway consisting of three footprints (one right, two left) with the two left prints exhibiting repetitive ichnopathology of a partially missing Digit II impression.
    Full-text · Article · Sep 2015 · Ichnos
    • "17–19). Theropod hallux impressions are not common, but they do occur and have been reported in the literature (Lockley and Hunt, 1994; Harris et al., 1996; Harris; 1997; McCrea, 2000; Lockley et al., 2004; Nouri et al., 2011; Xing et al., 2013c; McCrea et al., 2014a, b; Xing et al., 2014). The recognition of a small digit trace medial to the weight-bearing digits is sufficient to identify the impression as the hallux, a normal occurrence and not an example of polydactyly. "
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    ABSTRACT: One of the goals of vertebrate ichnology is to use trace fossils as an additional source of data to determine the palaeoecological makeup of vertebrate paleoecosystems. The features in both the synapomorphy-based and phenetic-based methods of attributing a trace to an osteologic trackmaker are those that are affected by preservational conditions, convergent due to size and/or habitat of the trackmaker, and are morphologically variable within taxa. Despite the drawbacks, the phenetic-based, or “gestalt” method, is still the most comprehensive, if not always synapomorphy-supported, means of using the largest amount of data (morphologic and behavioral) preserved for identifying tracks as avian. To date there are too few synapomorphies that are both pedes specific and are consistently preserved in footprints to be a practical method for attributing tracks to an avian trackmaker. There is still much more comparative ichnological and statistical work to be done to discern novel traits that can be used to delineate between the traces of large avian and small nonavian Mesozoic theropods.
    No preview · Article · Sep 2015 · Ichnos
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    • "E-mail: michela.contessi2@unibo.it Ait-Kaci Ahmed et al., 2004; Boutakiout et al., 2008; Belvedere et al., 2011; Mudroch et al., 2011; Nouri et al., 2011 "
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    ABSTRACT: Four vertebrate tracksites from the Middle Jurassic and Upper Cretaceous in the Tataouine basin of southern Tunisia are described. Approximately 130 tridactyl footprints distributed over an area of 200 square meters, preserved on Callovian beds exposed at the Beni Ghedir site, represent the oldest evidence of a dinosaur fauna in Tunisia. In addition, three tracksites—Chenini, Ksar Ayaat, and Jebel Boulouha—have been discovered in the Cretaceous beds of the upper Continental Intercalaire, previously considered as a strictly marine depositional sequence. In addition to dinosaur tracks, the Chenini tracksite (late Albian) includes poorly preserved crocodilian tracks, and footprints assigned to a pleurodiran turtle have been recovered at the Ksar Ayaat locality (early Cenomanian). The Jebel Boulouha tracksite is dominated by well-preserved tridactyl tracks referred to small-sized theropods. Depositional settings of each tracksite have been defined on stratigraphic and sedimentologic data, and tracks were ascribed to different ichnocoenoses in relation to their paleoenvironments. This new and differentiated track record gives important information on how the fossil vertebrate fauna changed in southern Tunisia during mid-Jurassic to mid-Cretaceous times. These data provide a unique and useful census of tetrapod associations along the southern margin of the peri-Mediterranean area.
    Full-text · Article · Dec 2012 · Ichnos
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